1. Field of the Invention
The present invention relates to a filling and packing machine by which a packing film extracted and guided from a film winding core and fed continuously is double-folded up along the longitudinal direction of the film and pack-target material is filled and packed while the four sides of the film thus folded up are sealed, and particularly a film folding and guiding apparatus for use in a filling and packing machine for feeding out a folded film to a predetermined position.
2. Description of the Related Art
A packing bag in which pack-target material such as liquid, powder or viscous material like sauce, soy sauce, mayonnaise or the like is filled and hermetically sealed is generally formed by sealing the four sides of a film in longitudinal and lateral directions.
One of filling and packing machines for filling and packing pack-target material while sealing the four sides of a film is disclosed in Japanese Laid-open Patent Application No. Sho-61-69521 or the like, for example. As disclosed in this publication, a pair of holding frames are provided at the side portion of the machine table of the filling and packing machine, and a film winding core around which a film is wound in the form of a roll is detachably and exchangeably supported by the holding frames. A film guide portion and a film folding portion are disposed at the upper portion of the machine table, and a longitudinal seal portion, a lateral seal portion and a cutter portion are disposed in this order from the upper side to the lower side of the front surface portion of the machine table.
According to the filling and packing machine disclosed in the above publication, the film is drawn out from the film winding core and guided through the film guide portion to the film folding portion. The film thus guided is double-folded up along the longitudinal direction thereof by the film folding portion, and both the side edges of the film is longitudinally sealed in a cylindrical form by the heated longitudinal seal portion. Thereafter, the film is laterally sealed in the lateral direction by the heated lateral seal portion to thereby form the bottom portion of a packing bag, and pack-target material such as liquid or the like is filled into the cylindrical film having the bottom portion by a filling nozzle of a filling machine. Thereafter, the cylindrical film is further fed and the open side thereof is laterally sealed by the heated lateral seal portion again to thereby seal the pack-target material. Thereafter, the middle portion of the laterally-sealed portion of the film is cut by the cutter portion, thereby achieving the four-side sealed packing bag, and the packing bag thus formed is fed by a conveyor or the like.
According to the conventional filling and packing machine as described above, the film is fed out while sealed by the longitudinal and lateral seal portions, and the speed of the sealing and packing work of the film can be increased by increasing the rotational speed of these seal portions. However, the film may be fed out while positionally displaced from a predetermined position due to irregular winding of the roll-shaped winding on the film winding core, variation of the tense of the film drawn out from the film winding core or the like. Therefore, if the film is fed from the film folding portion while the fold-up position of the film is deviated from a normal position, the longitudinal sealing position is displaced from a predetermined position, so that the sealing interval between both the side edges of the film by the longitudinal seal portion is dispersed, and in its turn, a sealing failure may occur.
Therefore, an object of the present invention is to provide a film folding and guiding machine for use in a filling and packing machine which can suppress the positional displacement of a fold-up packing film and feed the film to a predetermined position accurately.
In order to attain the above object, there is provided a film folding and guiding apparatus for use in a filling and packing machine, characterized by comprising: a film folding mechanism for double-folding a continuously-fed film drawn out and guided from a film winding core along the longitudinal direction of the film and is provided the upper portion side of a machine table of a filling and packing machine; a longitudinal sealing mechanism for longitudinally sealing at least both of right and left edge portions of the double-folded film which is folded up in a cylindrical form by a folding guide of the film folding mechanism; a lateral sealing mechanism that is provided below the longitudinal sealing mechanism and laterally seals the cylindrically-shaped film formed by the longitudinal sealing mechanism to form a bottom portion of a packing bag which will be formed; a filling mechanism for filling pack-target material into the cylindrically-shaped film having the bottom portion formed through the lateral sealing of the lateral sealing mechanism, a portion of the film which will serve as a bag open portion being laterally sealed by the lateral sealing mechanism while the film is fed, thereby forming a packing bag that is heat-sealed at the four sides thereof; a cutter mechanism for cutting a laterally-sealed portion of the packing bag which is sealed at the four sides thereof; and a film guide member that is located between the film folding mechanism and the longitudinal sealing mechanism so as to be adjacent to the longitudinal sealing mechanism, and holds and regulates the outer surface portions of the folded portions of the double-folded film, thereby suppressing the positional displacement of at least both the right and left edge portions of the double-folded film which is folded up and guided and accurately sealing both the edge portions of the film in a proper positional relationship.
According to the present invention, the tip portion of the folding guide provided to the film folding mechanism is disposed so as to be approximate to a longitudinal heat seal roll of the longitudinal sealing mechanism, and the film guide member is provided so as to confront the folding guide, whereby the film to be folded and guided is guided to the longitudinal heat seal roll position of the longitudinal sealing mechanism along the folding guide, drawn out and guided without any positional displacement in the lateral direction and then longitudinally sealed at a predetermined position.
Further, according to the present invention, the film guide member is urged against the folding guide under soft pressure through the folded portions of the double-folded film, whereby the film can be fed while a load acting on the feeding of the film in the lateral direction can be absorbed by the film guide member, and also the film can be held at a predetermined position without applying large force to the film to perform a stable film feeding operation.